1. Field of the Invention
The present invention relates to a vehicle body structure for a motorcycle which can improve the rigidity of a vehicle body without increasing the width or the weight of the vehicle body.
2. Description of Background Art
A vehicle body structure for a motorcycle is known wherein main pipes extend rearwardly from a head pipe with a pair of left and right down tubes extending from the head pipe obliquely downwardly toward the rear and with an engine disposed between the main pipes and down tubes.
In this vehicle body structure of a motorcycle, front hangers are attached to the extremities of the pair of left and right down tubes and a rear hanger is mounted adjacent to the main pipes for supporting the engine.
A vehicle body structure for a motorcycle as described above is disclosed in JP-A-9-95278 wherein the vehicle width of the motorcycle is reduced by providing the front hangers formed of a plate member at the extremities of the down tubes.
FIG. 8 is a drawing that corresponds to FIG. 2 in JP-A-9-95278, wherein the reference numerals have been changed as compared to the reference numerals as used in JP-A-9-95278.
A vehicle body structure for a motorcycle in JP-A-9-95278 includes main pipes 3 extending from a head pipe 2 rearwardly with a pair of left and right down tubes 6, 6 extending from the head pipe 2 obliquely downwardly towards the rear. Plate shaped front hangers 11, 11 are attached to the extremities of the down tubes 6, 6 with an engine (not shown) being supported by the front hangers 11, 11 and the main pipes 3. Four exhaust pipes 17 . . . extend from the engine ( . . . represents that there are a plurality of members, hereinafter) and pass insides the down tubes 6, 6.
However, the vehicle body structure for a motorcycle in JP-A-9-95278 has a problem in that when the diameters of the down tubes 6, 6 are increased for improving the rigidity of the vehicle body. The exhaust pipes 17 . . . extending from cylinders of the engine respectively tend to interfere with the down tubes 6, 6, whereby the width of the motorcycle is obliged to be increased in order to eliminate this interference.
In addition, the vehicle body structure for a motorcycle in JP-A-9-95278 has a problem in that, for example, the weight of the vehicle body increases when attaching reinforcing members are added to the down tubes 6, 6 for improving the rigidity of the vehicle body, whereby the weight of the vehicle body cannot be maintained.